(19)
(11) EP 0 298 418 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
24.04.1991 Bulletin 1991/17

(43) Date of publication A2:
11.01.1989 Bulletin 1989/02

(21) Application number: 88110704.9

(22) Date of filing: 05.07.1988
(51) International Patent Classification (IPC)4G06F 9/46
(84) Designated Contracting States:
DE FR GB

(30) Priority: 08.07.1987 JP 168636/87

(71) Applicant: HITACHI, LTD.
Chiyoda-ku, Tokyo 100 (JP)

(72) Inventors:
  • Nakayama, Shinji
    Hadano-shi (JP)
  • Watanabe, Masaya
    Hadano-shi (JP)
  • Abe, Shuichi
    Hadano-shi (JP)

(74) Representative: Altenburg, Udo, Dipl.-Phys. et al
Patent- und Rechtsanwälte, Bardehle . Pagenberg . Dost . Altenburg . Frohwitter . Geissler & Partner, Galileiplatz 1
81679 München
81679 München (DE)


(56) References cited: : 
   
       


    (54) Virtual computer system


    (57) In the conventional virtual computer system, in order to provide the same access method for the host and the guest, there exists a great overhead for the operations to save and to restore the host resource at a change-over between the host and the guest. In the disclosed system, the same access method is provided for the host and the guest and at the same time the overhead is removed. The host resource (11) and the guest resource (12) are separately allocated. There is disposed a mode line (5) indicating whether the present state is associated with the host or the guest. There is also disposed an access controller (2, 3) which operates such that when the mode line indicates the host, the host resource is accessed, and when the guest is indicated, the guest resource is accessed.







    Search report